WCF Service Error accessing DB

I have a WCF Service running under IIS 7.0. The app pool ide开发者_JS百科ntity is set to a user account lets call it "MyDomain\MyAcc." I have given "MyDomain\MyAcc" login permissions to the SQL 2005 Server, and the two DBs that it uses on that server.

When I try to invoke one of the WCF methods I get the following in my logs: "Login failed for user 'MyDomain\MyAcc'..." I have tried removing and re-adding that user on the SQL Server.

I also tried accessing the DBs from Management Studio running as "MyDomain\MyAcc" and that worked.

What am I missing?

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Finally Figured it out, we are using LINQ to SQL and the last guy who checked the code in commented out the code that we used to pass in the connection string from the web.config file. So it was using the connection string from the dbml file instead. That connection string was pointing to a DB that the user account did not have access to.